It is of crucial importance for efficient and problem-free operation of the cooling tower for the water to trickle through the interior of the cooling tower as uniformly and slowly as possible so that it can give up as much heat as possible to the cooling air. Soiling or foreign objects prevent uniform distribution and slow trickling of the water through the tower and therefore reduce its efficiency. If there are foreign particles in the cooling water there is the possibility of filtering these particles out. In any case the moist and warm conditions within a cooling tower disadvantageously promote the formation of microorganisms, for example algae and/or fungi. For this reason it is necessary, in order to guarantee problem-free and efficient operation of a cooling tower, to clean the inserts that are situated within the tower, for example the cooling inserts, pipelines and collectors, since the plugging of cross sections through which water trickles or flows by microorganisms growing on the inserts would likewise give rise to reduced cooling efficiency or failure of the cooling tower. Such cleaning operations disadvantageously give rise to high costs and additionally necessitate interruption of cooling tower operation. In the region of the cooling inserts there have been attempts to reduce their soiling by means of various cooling insert designs, for example film packages, trickle lattices, drip gratings or drip boards, or to increase the insensitivity of the cooling inserts to soiling. However, to achieve a cooling effect that is as high as possible and cooling tower operation that is as efficient as possible it is advantageous to conduct the water to be cooled in a finely divided form and as slowly as possible through the cooling inserts and in this way to achieve a long residence time of the water in the cooling air flow. However, the slow trickle rate of the water favors the formation of algae. An increase of the water trickle rate, conversely, reduces the cooling efficiency achieved with the help of a cooling insert. Partial plugging of the cooling insert cross section through which the water and cooling air flow not only reduces the efficiency but, because of the necessary cleaning, gives rise to high costs, additionally the operating costs rise in the case of cooling towers that push the air through with the aid of blowers, since an increased blower efficiency is necessary in order to pump the necessary cooling air flow through the cooling tower. For this reason the degree of soiling should also be kept as low as possible for reasons of energy consumption.